This UCLA Symposium will present critical data on the basic science and clinical treatment of human retroviruses, including oncogenic retroviruses HTLV-I and HTLV-II and immunodeficiency retroviruses HIV-I and HIV-II. By 1989, other human retroviruses will have been identified and characterized, and progress in vaccine development, pathogenesis of oncogenic transformation or cytopathic effects, and treatment interventions will be discussed. This meeting will be a coherent synthesis of the best work in the field, which has been designed to be particularly appealing to new and/or young investigators. The intimate setting and relatively small size of the meeting should be conducive to a high level of communication and cooperation.